flutter how to check if a String contains at least one String from a list of Strings

Question

I want to check if the value that the user enters in a TextFormField contains at least one String in another given String.

As an example, if the given String value is 0123456789 and if the user enters Ab3 in the TextFormField, how to check if the user entered value contains at least one String in the given String?

 String allowedChar = "0123456789";
 final split = allowedChar.split('');

I tried splitting the given value like this and checked if the textEditingController.text contains the value for each splitted value of allowedChar.

if (_value.isNotEmpty &&
  textEditingController.text.contains(c)) {
    _areAlwdCharsTyped = true;
} else if (!textEditingController.text.contains(c)) {
    _areAlwdCharsTyped = false;
}

But _areAlwdCharsTyped always returns false. Could I know a way to achieve this please? Thanks in advance.

Ουιλιαμ Αρκευα · Accepted Answer · 2021-04-27 16:27:16Z

1

void main() {
  const text = 'Ab3';
  var match = RegExp(r'\d').hasMatch(text);
  
  print(match);
}

Result

true

answered Apr 27, 2021 at 16:27

Ουιλιαμ Αρκευα

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1 Comment

Haritha Madhushanka Over a year ago

Thank you for taking time to answer my question, sir. But the thing is allowedChar can change, since it's coming from an api call. Even though the allowedChar value is 0123456789 at the time, it could change to something else.

user2233706 · Accepted Answer · 2021-04-27 16:56:19Z

0

I think you're close. You can iteratively check whether the input string contains any of the chars in allowedChars.

void main() {
 String allowedChar = "0123456789";
 final split = allowedChar.split('');
 final str = 'AB3';
 final str2 = 'AB';
  
 print(split.fold<bool>(false, (prev, element) => str.contains(element) || prev)); // true
 print(split.fold<bool>(false, (prev, element) => str2.contains(element) || prev)); // false
}

answered Apr 27, 2021 at 16:56

user2233706

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